Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
  • F02C7/36—Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D15/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
  • F01D15/12—Combinations with mechanical gearing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
  • F02C3/04—Gas-turbine plants characterised by the use of combustion products as the working fluid having a turbine driving a compressor
  • F02C3/107—Gas-turbine plants characterised by the use of combustion products as the working fluid having a turbine driving a compressor with two or more rotors connected by power transmission
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H1/00—Toothed gearings for conveying rotary motion
  • F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
  • F16H1/20—Toothed gearings for conveying rotary motion without gears having orbital motion involving more than two intermeshing members
  • F16H1/203—Toothed gearings for conveying rotary motion without gears having orbital motion involving more than two intermeshing members with non-parallel axes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
  • B64D35/00—Transmitting power from power plant to propellers or rotors; Arrangements of transmissions
  • B64D35/02—Transmitting power from power plant to propellers or rotors; Arrangements of transmissions characterised by the type of power plant
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/30—Arrangement of components
  • F05D2250/31—Arrangement of components according to the direction of their main axis or their axis of rotation
  • F05D2250/312—Arrangement of components according to the direction of their main axis or their axis of rotation the axes being parallel to each other
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/30—Arrangement of components
  • F05D2250/31—Arrangement of components according to the direction of their main axis or their axis of rotation
  • F05D2250/314—Arrangement of components according to the direction of their main axis or their axis of rotation the axes being inclined in relation to each other
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2260/00—Function
  • F05D2260/40—Transmission of power
  • F05D2260/403—Transmission of power through the shape of the drive components
  • F05D2260/4031—Transmission of power through the shape of the drive components as in toothed gearing
  • F05D2260/40311—Transmission of power through the shape of the drive components as in toothed gearing of the epicyclical, planetary or differential type
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the present invention relates to the aeronautical field and relates to a propulsion assembly comprising at least one blower driven by a motor. It is more particularly a power transfer system between the engine and the fan that it drives.
• a block diagram of a propulsion assembly 1 with at least one blower is shown in Figures 1 and 2.
• This power shaft 6 drives through appropriate bevel gear pairs two radial intermediate shafts 8 and 8 'arranged in particular at right angles to the axis of the power shaft 6.
• the intermediate radial shafts each drive a fan shaft 9, 9' offset, c 'with axis offset from the axis of gas generator.
• the transmission of power is effected by means of first gears 2 and 2 'with bevel gears between the shaft 6 and the radial shafts 8 and 8' and second gears 4 and 4 'with bevel gears between the radial shafts 8, 8 and the fan shafts 9 and 9 '.
• the solution to the transmission problem between the free turbine and the fan shaft (s) is to use, for each of the blowers, simple 45 ° conical gears: a first gear with two wheels of the same diameter, one on the shaft of the free turbine and the other on the radial shaft and a second conical engagement at 45 ° with two wheels of different diameters connecting the radial shaft to that of the fan.
• the first gear can have two different diameter wheels and the second meshing can have two wheels of the same diameter.
• the input gear of the first gear 2 of the assembly shown in FIG. 2 is dimensioned so as to take the constraints relating to the turbine torque, which gives an incompressible minimum pitch diameter for the latter, and thus fixes its dimensions. .
• the reduction ratio of the bevel gear is then obtained by adjusting the size of the wheel fixed on the radial shaft. For high reduction ratios, especially greater than 2.5, it can be seen that the wheel in direct conical engagement with the central gear then poses a congestion problem because of the large diameter thereof.
• the present invention aims to remedy this problem.
• a propulsion unit of an aircraft comprising at least one turbine, at least one fan, and a power transmission mechanism between the turbine and the fan, the power transmission mechanism comprising a power reducer.
• speed with an input and a movement output the inlet being connected to the turbine and the output connected to the fan
• the speed reducer being an epicyclic reduction gear with a sun gear, satellites and a ring gear, the sun gear forming the input and the ring forming the output of the reducer, and the axis of rotation of the satellites being inclined relative to the axis of the sun gear.
• the fan is of axis offset with respect to the axis of the turbine.
• the fan is of axis coaxial with the axis of the turbine.
• the input of the speed reducer is in the extension of the axis of the turbine.
• the shaft of the turbine is engaged in the axis of the central sun gear.
• the reducer is thus in its prolongation.
• the wheels of the satellites are guided in rotation and supported by a stator frame which can be arranged so that the wheels of the satellites form an angle with the axis of the turbine.
• the orientation of the satellites also makes it possible to obtain a gearbox with a conical or spherical shape that optimizes the space available in the exhaust cone.
• the angle of inclination of the satellite wheels is determined (axial axial iso) by the reduction ratio of the speed reducer together with the ratio of the pitch diameters between satellites and crown as well as by the bending and pressure stresses allowed in the teeth (the increase of the original diameter of the sun gear reduces the stresses in it to iso torque) and the total length of the gearbox.
• the pinions of the satellites may have a larger diameter than the pinion of the input sun gear.
• the reduction ratio of the epicyclic speed reducer depends solely on the ratio between the diameter of the input sun gear and the diameter of the output ring gear.
• the gearbox is here a spherical reducer for a transmission between the crown and the radial shaft with small diameter wheels (close to the diameter of the sun gear input) and a reduction ratio as low as possible. Thanks to the spherical speed reducer, a gearbox gear is arranged on the canvas of the output ring, small diameter which allows to transmit by means of small wheels and at low speed movement to the blowers.
• a conventional epicyclic gearbox with a ring gear and a bevel gear fitted on the high-diameter ring gear requires a speed-reducing gearbox then an angle gear that accelerates it, which multiplies the yield losses in the gearbox. gear.
• a spherical reducer also allows a reduced radial size for the same reduction ratio. These characteristics correspond well with the space available under turbine.
• the ring comprises a first pinion meshing with the satellites and a second pinion concentric with the first forming the output of the speed reducer. More particularly, the second gear is of smaller radius than the first gear.
• the power transmission mechanism comprises at least one intermediate shaft oriented in a radial direction relative to the axis of the turbine, the intermediate shaft being engaged with the output of the speed reducer.
• the power transmission mechanism comprises two homokinetic joints.
• Homokinetic joints are arranged between the speed reducer and the turbine.
• the power turbine shaft may carry a bevel gear that drives a substantially identical diameter wheel.
• the transmission is at this level without speed reduction of the shaft line.
• This first angular gear can be arranged also with speed reduction of the shaft line.
• This option with speed reduction is advantageous in the case where a very large total reduction ratio is provided. It limits the dimensions of the main gearbox on the fan shaft.
• the reduction ratio of the return stage remains low, related to considerations, on the one hand integration of the angle gear in the exhaust casing and the radial shaft in the arms of casing and on the other hand holding the turbine shaft gear to bending stresses and pressure.
• the radial shaft is thus a fast shaft of rotational speed substantially identical to that of the power turbine.
• the power transmission mechanism comprises a first intermediate shaft element oriented in a radial direction relative to the axis of the turbine, the first intermediate shaft element meshing with the shaft. of the turbine.
• the transmission mechanism comprises a second radial intermediate shaft element, between said first shaft element and the second shaft element being arranged a link comprising the two homokinetic joints.
• connection between the two intermediate shaft elements comprises a slide connection arranged in series with the two constant velocity joints.
• the invention advantageously applies to a propulsion assembly whose turbine is driven by a gas generator.
• propulsion assembly whose gas generator is a gas turbine engine with an exhaust casing comprising two concentric rings, one internal and the other external, defining the vein of the engine gases in downstream of the turbine.
• the reducer is housed inside the inner shell.
• the intermediate shaft passes through the ferrules of the exhaust casing.
• the first intermediate shaft element passes through the ferrules of the exhaust casing.
• the invention also relates to a propulsion assembly of an aircraft comprising a turbine, at least one fan driven by an axis shaft offset from the axis of the turbine and a power transmission mechanism between the turbine and the turbine.
• blower characterized in that the power transmission mechanism comprises a speed reducer on the drive shaft of the blower, the speed reducer being an epicyclic gear with a sun gear, satellites and a ring gear, the pinion planetary forming the input of the reducer.
• Figure 1 is a schematic representation of an aircraft propulsion assembly architecture
• FIG. 2 shows an arrangement of the bevel gears in the drive of the fan shaft by the turbine shaft according to the architecture of FIG. 1;
• Figure 3 shows a schematic representation of the power transmission according to an embodiment of the invention
• Figure 4 shows an example of integration of the power transmission of the invention into a motor structure
• Figure 5 shows a detail of the transmission of Figure 4.
• Figure 6 shows another detail of the transmission of Figure 4
• Figures 7a and 7b show a schematic representation of the power transmission according to one embodiment of the invention with a plane planetary gear train
• FIG. 8 shows a schematic representation of the power transmission according to another embodiment of the invention with a epicyclic gear whose axis of the satellites is inclined relative to that of the sun gear;
• Figure 9 shows an arrangement of the bearings of the transmission along the fan axis.
• Figure 10 schematically illustrates another embodiment of a propulsion assembly with at least one blower upstream of a gas generator.
• the invention relates to a propulsion assembly of a turbomachine of an aircraft.
• the propulsion assembly includes a gas generator, at least one blower and at least one power transmission mechanism.
• the gas generator comprises from upstream to downstream at least one compressor, a combustion chamber and a turbine.
• upstream and downstream are defined with respect to the flow of gas in the turbomachine.
• the gas generator comprises a power turbine with a longitudinal axis X.
• the power turbine 15 is driven by the gases of the gas generator.
• the X axis of the turbine is coaxial with that of the gas generator.
• the power transmission mechanism is arranged between the turbine and a blower.
• the gas generator is a gas turbine engine with an exhaust casing 30. The latter comprises two concentric rings, an inner shell and an outer shell which define the vein of the engine gases downstream of the turbine.
• the propulsion assembly comprises at least one remote shaft blower, offset relative to the axis of the gas generator.
• the set propulsion system comprises two remote axis blowers.
• the power transmission mechanism is arranged between the turbine and each blower.
• the power transmission mechanism schematically illustrated in Figure 3 comprises at least one speed reducer with an input and a moving output.
• the inlet is connected to the turbine 15 and the outlet is connected to the fan 10.
• the turbine 15 comprises a turbine shaft 16 rotatably mounted on a bearing 1 6p integral with the fixed structure of the engine.
• This shaft 1 6 is connected to the speed reducer 20 here epicyclic gear.
• the shaft 1 6 is extended axially to a toothed wheel 21. The latter forms the input wheel of the reducer.
• the axis of the wheel 21 is coaxial with the turbine shaft 1 6.
• the epicyclic gear reducer 20 further comprises the satellites 23 and the ring 27.
• the ring 27 of cylindrical shape is rotatably mounted in a bearing 27p integral with the fixed structure of the engine.
• the planet wheels 23 are supported in a stationary frame 25 fixed to the fixed structure of the engine. As can be seen in the figure, the axis of rotation of the planet wheels is not parallel to the axis of the shaft 1 6 but inclined with respect thereto.
• the inclination of the satellites makes it possible to reduce the radial size of the gearbox relative to a device in which the axes are parallel to one another.
• the outlet of the gearbox is formed of the annular toothing 27c2 of the ring 27.
• This annular toothed area 27c2 is centered on the axis of the shaft 1 6. Its radius is notably smaller than that of the annular toothing.
• the link between the output of the gearbox and the fan 10 is formed by at least one intermediate shaft 18. More specifically, the drive of the fan 10, shaft 19 parallel to the turbine shaft 1 6, is carried out by the intermediate shaft 18, radial with respect to the shaft 1 6 of the turbine.
• This intermediate shaft 18 is connected on the one hand, at its radially upper end, to the fan shaft 19 by an angular gearing gear 14, the latter comprising the bevel gear 18c2 of the intermediate shaft 18 and secondly at its radially lower end by a bevel gear 18c1 to the annular tooth 27c2 output of the ring 27.
• the bevel gear by means of the Angle transmission gear 14 is made of C1 rather than C2 (see FIG. 3) by virtue of the configuration of the spherical speed reducer which makes it possible and facilitates the connection of a small-diameter deflection wheel C1. Indeed, the diameter of the wheel is less important than C2.
• the intermediate shaft 18 rotates at a reduced speed relative to that of the turbine shaft 1 6.
• the reduction in speed results from the ratios between the spokes of the pinions and toothed wheels, 21/23, 23 / 27c2, 27c1 / 27c2 as well as the inclination of the planet wheels 23.
• the diameter of the pinion 18c2 is not greater than that of the pinion 18c1 so as not to accelerate the fan shaft.
• the inclination of the satellite wheels is not imperative to the speed reduction function but it brings the additional advantage of reducing the diameter of the gearbox allowing its introduction into the exhaust casing of an aircraft engine.
• Figures 4, 5 and 6 show a practical example of arrangement of the elements of the power transmission mechanism of the invention, in the structure of an engine comprising a gas turbine engine gas generator.
• the gearbox 20 is disposed at the end of the turbine shaft 1 6, It forms a module housed in a ferrule 35 of structural housing which itself is integral with the exhaust casing 30 of the engine.
• This exhaust casing comprises a radially inner ferrule 32 and a radially outer ferrule 31 connected by radial arms 33. These two ferrules form between them an annular channel forming the vein of the gases from the power turbine.
• the ferrule 35 is closed axially by a cover 37.
• a rotating shell 28 comprising the ring 27 is rotatably mounted inside the fixed shell 35 in a first bearing 27p (see Figure 5).
• the bearing 27p is a bearing on balls.
• the bearing 27p disposed at the axial end of the gearbox is arranged to also form an axial stop.
• the inner ring of the bearing 27p is carried by the rotating shell 28 and the outer ring is carried by the fixed shell 35.
• a roller bearing (not shown) is provided between the rotating shell 28 and the casing so as to ensure the rotation guide of the rotating ferrule 28.
• the ring 27 also comprises an inner cylindrical bearing surface 27t at least partially covering the shaft of the sun gear 21 and taking a rotary bearing on it via a bearing 27r, for example with rollers. More specifically, the bearing 27r is disposed towards the distal end of the inner cylindrical bearing surface 27t. The inner ring of the bearing 27r is carried by the inner cylindrical bearing surface 27t and the outer ring is carried by the sun gear 21. This configuration makes it possible to have a fairly large spacing between roller bearings and balls and to improve the quality of the guidance in rotation of the crown.
• This shaft of the sun gear 21 is located in the extension of the turbine shaft 1 6 to which it is connected by a splined coupling.
• the sun gear is supported by a bearing 21 p also forming axial stop.
• the bearing 21 p is a ball bearing.
• the bearing 21 p is housed in the support frame of the satellites.
• the inner ring of the bearing 21 p is carried by the distal end of the shaft of the sun gear 21 and the outer ring is carried by the frame.
• the frame is itself secured to the housing shell 35.
• the ring 27 is rigidly mounted and the frame 25 and the turbine shaft 1 6 are mounted so as to limit the flexibility of the hyperstatism in the reducer, and therefore its wear.
• the shaft 1 6 turbine is flexible through the splines and bellows on the shaft upstream of the reducer.
• the splines allow to transmit the torque between the two shafts but leave the possibility of limited axial sliding of one relative to the other to absorb at this level structural deformations in operation.
• the frame is flexible mounted with a pin surrounding the bearing 27p (see Figure 5). Thus the transmission of vibrations generated by the reducer to the structure is limited.
• the planet wheels whose axis of rotation intersects that of the shaft 1 6 of the turbine, are for example three in number supported by the frame 25 being mounted in bearings 23p.
• the rotation guidance of the satellites is ensured for example by means of spherical roller bearings, making it possible to produce an equivalent ball joint connection which makes the gearbox tolerant to misalignment between the input and output members.
• the piece 27 carrying out the crown function here has the peculiarity of having a toothed annular zone 27c1 in which meshes the planet wheels 23 and also a toothed annular zone, situated at a pitch diameter substantially smaller than the preceding one, and situated for example on the opposite side.
• This second toothed zone makes it possible to transmit the power to the intermediate shafts 18, here radial, and is dimensioned so as to facilitate the integration of the internal wheel 18c1 of the intermediate shafts 18.
• the pitch diameter of the second toothed annular zone of the crown is chosen. the smallest possible considering the mechanical constraints.
• pitch diameter of the inner wheel of the intermediate shaft 18 be at least equal to that of this second tooth zone so as not to increase the speed of rotation of the output shaft of the gearbox and eliminate the effect of the reducer.
• the intermediate shafts 18 are placed in the same plane so that the lateral loading of the bearings of the ring 27 is limited.
• the intermediate shafts 18 may be arranged in different planes transverse to the shaft 1 6 of the turbine.
• the mechanical stresses due to the arrangement of the blowers are limited.
• FIG. 7a A second embodiment of the arrangement of the power transmission mechanism according to the invention is illustrated schematically in FIG. 7a.
• the corresponding reference numerals of the propulsion assembly described above in the first embodiment are retained hereinafter in the description.
• the propulsion assembly here comprises two blowers offset with respect to the axis of the turbine.
• the drive assembly could include a single remote blower.
• the power transmission mechanism comprises at least one speed reducer 300 and a radial transmission 200.
• the shaft 1 6 turbine is rotatably mounted on a set of bearings 16p1, 1 6p2, integral with the fixed structure of the motor: a bearing 1 6p1 roller and a bearing bearing 16p2 for example a ball bearing.
• This shaft 1 6 is connected to the radial transmission 200 by a bevel gear with bevel gears one 16c on the turbine shaft 1 6 and the other 210c on a first radial intermediate shaft member 210.
• the simple angle gear in the gas generator facilitates the integration of it into the exhaust casing.
• This first shaft element 210 is connected to a second radial intermediate shaft element 220 via a link 230 of the radial transmission.
• the link 230 is schematized here by two homokinetic joints 23c1, 23c2 in series with each other with a slide connection 23g. These constant velocity joints are of the finger ball type. This combination makes it possible to make up for the angular displacements between the first and second shaft elements and also the axial displacements between them, which are likely to occur during the operation of the propulsion assembly due to the thermal and mechanical loadings.
• the first constant velocity joint is a Rzeppa seal.
• a seal comprises a drive shaft and a driven shaft; a bowl is attached to an axis and a nut is secured to the other axis with the interposition of balls.
• the arrangement between these elements is made so as to allow a drive of the driven axis at the same speed of rotation as the input axis while admitting an angular misalignment between them.
• the second constant velocity joint is a sliding VL seal. It comprises a drive shaft and a driven shaft; balls retained in a cage are movable inside cross grooves, respectively outer and inner. The grooves allow axial displacement of one axis relative to the other while ensuring the transmission of torque.
• the second seal can also be a Rzeppa seal. The connection between the two joints then being sliding, for example by means of sliding splines.
• the second shaft member 220 is connected by a bevel gear to a third fan drive shaft member 10.
• the bevel gear includes the two bevel gears 220c and 110c.
• the fan 10 is driven by its fan shaft 19 which is itself driven by the third shaft element 1 10 through the speed reducer 300 supported by the fan module.
• the gearbox is preferably epicyclic gear with a sun gear 310, a ring 350 and satellites 330.
• the satellites 330 are supported by a fixed frame 340, attached to the casing 30 of the propulsion unit.
• the wheels forming the satellites 330 mesh on the one hand, on the teeth of the sun gear 310 and on the other hand on the teeth of the ring gear 350.
• the sun gear 310 meshes with the set of satellites, the number of which depends on the size gearbox, reduction ratio and input torque.
• satellites are, according to one embodiment, double helical helical gears.
• restores the degree of freedom in axial translation between each component For example, it is possible for this purpose to use satellite guidance by means of smooth without axial stop and a fan / crown rotor connection made using a groove not locked axially and thus sliding on the axis of the fan.
• satellites are according to another embodiment with straight teeth.
• the degree of freedom in axial translation is maintained between planet / satellites and satellites / crown.
• the third shaft element 1 10 engages, at the input of the gearbox, with the sun gear 310 and, at the output, the fan shaft 19 is driven by the ring 350 of which it is integral.
• the shafts 1 10 and 19, supported by sets of bearings 1 10p and 19p to the fixed structure of the propulsion assembly, are here coaxial in the direction A which is parallel and offset from the direction B of the shaft 1 6 turbine.
• the bearings 19p and 10p are respectively a ball bearing and a roller bearing.
• the third shaft element 1 10 is supported by the roller bearing 1 10p which is arranged upstream of the speed reducer 300 between a support ring 40 and the shaft 1 10.
• the inner ring is carried by the third shaft member 1 10 and the outer ring is carried by the support ferrule.
• the ball bearing 19p it is disposed downstream of the speed reducer 300, near the blower, between a pin 29 secured to the housing arm 280 and the fan rotor 26.
• the outer ring is carried by the fan rotor 26 and the inner ring is carried by the pin 29.
• This ball bearing 19p forms an axial stop. In this way, the fan rotor 26 is guided in rotation and is held axially in position.
• the crown is mounted flexibly and the sun gear is rigidly mounted.
• first and second shaft members 210, 220 radial see a lower torque, it follows a gain in mass thereon.
• the casing arms allowing passage of the first and second radial shaft elements are smaller, and the associated losses in the primary and secondary veins are reduced.
• the kinematic chain between the turbine 15 and the fan 10 thus comprises the shaft 1 6, the radial transmission 200, the third shaft element 1 10, the speed reducer 300 and the fan shaft 19.
• the wheels of the satellites are guided in rotation and supported by a stator frame which can be arranged so that the wheels of the satellites form an angle with the axis of the turbine.
• the angle of inclination of the satellite wheels is determined at iso axial size by the ratio of reduction of the speed reducer together with the ratio of the pitch diameters between satellites and crown as well as by the bending stresses and pressure allowable in the teeth (Increasing the pitch diameter of the sun gear reduces the stresses in it to iso torque) and the overall length of the gearbox.
• the gearbox 300 comprises an input sun gear 310' and an output ring gear 350 'for driving the fan shaft.
• the satellites are mounted on a chassis 340 'integral with the engine structure and their axis of rotation instead of being parallel to the axis of the sun gear are convergent with it.
• the inclination of the satellites makes it possible to reduce the radial size of the gearbox relative to a device in which the axes are parallel to one another. Such inclination also makes it possible to obtain a gearbox with a conical or spherical shape which optimizes the space available in the fan module (s).
• the spherical reducer allows a reduced radial space requirement for the same reduction ratio.
• FIG. 9 shows a fan module assembly incorporating an example of a bearing arrangement for a spherical reducer, inside a fixed housing element 340 'which notably comprises the planet carrier.
• the second radial shaft element 220 of the radial transmission is supported in the housing element 340 'by means of two bearings 22: a ball bearing 22p1 and a roller bearing 22p2.
• the third shaft member 1 10 ' comprises on one side the bevel gear 1 10'c of the bevel gear and on the other hand the sun gear 310' of the gearbox 300 '. It is supported on one side by a roller bearing 1 10'p2 and on the other side inside the gearbox 300 'by an inter-shaft bearing 1 10'p1.
• the roller bearing is disposed between the bevel gear 1 10'c and the sun gear 310 '.
• the inter shaft bearing is at the end of the fan shaft 19 which is integral with the ring 350 '.
• the fan shaft 19 is also supported by a double bearing with a roller bearing 19p1 and a ball bearing 19p2. Radial bearings see lower loads. The radial shafts see a lower torque, it follows a gain in mass on this component.
• a ball bearing is incorporated whose outer ring is carried by the casing and not a rotor.
• the counter-rotating shaft bearing can also be the roller bearing, preferably because the thrust bearing would then be closer to the conical engagement, contributing to the good quality of the power transfer (few displacements).
• the satellites 330 'of the gearbox are preferably supported by a spherical roller bearing which ensures satisfactory guidance while making it tolerant to possible defects. alignment between the two shafts 19 and 1 10 'during operation of the propulsion assembly.
• the ring is connected to the fan module housing and the satellite door connected to the rotor of the fan.
• FIG. 10 illustrates another embodiment of a propulsion assembly of an aircraft turbomachine.
• the corresponding numerical references of the propulsion assemblies described above in the first and second embodiments are retained hereinafter in the description.
• the propulsion assembly comprises a gas generator 50, a fan 10 mounted upstream of the gas generator 50 along a longitudinal axis X and a power transmission mechanism.
• the gas generator 50 comprises upstream-downstream, a low-pressure compressor 51, a high-pressure compressor 52, a combustion chamber 53, a high-pressure turbine 54 and a low-pressure turbine 55.
• the low-pressure turbine 55 corresponds to the power turbine.
• the low pressure compressor 51 and the low pressure turbine 55 are connected by the low pressure turbine shaft.
• the high pressure compressor 52 and the high pressure turbine 54 are connected by a high pressure shaft 56.
• the power transmission mechanism is arranged between the fan 10 and the turbine 55.
• the drive of the fan 10 is carried out by the fan shaft 19 coaxially axially substantially with the turbine shaft 1 6.
• the power transmission mechanism also includes an epicyclic type speed reducer 400.
• the gearbox 400 comprises a sun gear 410, satellites 420 and a ring gear 450.
• the sun gear 410 forms the input of the gearbox and the ring gear 450 the output of the gearbox.
• the sun gear 410 is connected to the shaft 1 6 turbine and the ring 450 is connected to the fan shaft 19.
• the planet gear 410 meshes with a satellite wheel 420.
• the latter meshes with the ring gear 450 which drives the fan shaft 19.
• the axis of rotation of the planet wheels is also inclined with respect to the axis of the sun gear.
• the axis of the sun gear is coaxial with the axis of the turbine 16.
• the shaft of the sun gear 410 is located in the extension of the turbine shaft 1 6 to which it is connected by a splined coupling.
• the sun gear is supported by a bearing 21 p also forming axial stop.
• the bearing 21 p is a ball bearing.
• the bearing 21 p is housed in the support frame of the satellites.
• the inner ring of the bearing 21p is carried by the distal end of the shaft of the sun gear 410 and the outer ring is carried by the frame 25.
• the frame is itself secured to the housing shell 35 fixed and connected to the inlet casing of the turbomachine.
• the ring 450 of cylindrical shape is rotatably mounted via a bearing 27p integral with the fixed structure of the engine.
• the rotating ferrule 28 including the crown 450 is rotatably mounted within the ferrule 35 in the 27p.
• the bearing 27p is a ball bearing.
• the bearing 27p, disposed at the axial end of the gearbox, is arranged to also form an axial stop.
• the inner ring of the bearing 27p is carried by the rotating ferrule 28 and the outer ring is carried by the ferrule 35.
• the ring gear 450 also includes the inner cylindrical bearing surface at least partially covering the shaft of the sun gear 410 and taking a rotary bearing on it via the bearing 27r, here with rollers.
• the bearing 27r is disposed towards the distal end of the inner cylindrical bearing surface 451.
• the outer ring of the bearing 27r is carried by the inner cylindrical bearing surface 450 and the inner ring is carried by the sun gear 410.
• Such a configuration also reduces the radial size.

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• 2016
  • 2016-10-05 EP EP16790669.2A patent/EP3359791B1/fr active Active
  • 2016-10-05 CN CN201680060514.3A patent/CN108138658B/zh active Active
  • 2016-10-05 US US15/765,450 patent/US11022043B2/en active Active
  • 2016-10-05 WO PCT/FR2016/052562 patent/WO2017060623A1/fr active Application Filing

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